The present invention relates generally to coin testing apparatus for discriminating between genuine and non-genuine coins, tokens and the like and more particularly to coin testing devices suitable for use with gaming devices.
Gaming devices such as slot machines require a device known as a coin acceptor to detect and signal insertion of a valid token or coin to render the gaming device operable. Coin acceptors for gaming devices preferably perform several functions. These include detection of the proper size and weight of the coin, the insertion of a counterfeit coin or slug (by checking for metallic content and/or diameter interruption) and in the case of multiple coin machines, detection of a cheating method commonly referred to as "stringing".
Numerous types of coin testing devices are available but many are inappropriate for use in the gaming industry because the testing procedures require too much time to complete. With existing mechanical coin acceptors, the coin is usually weighed with a rocker arm with a counterbalance and then bounced off some type of small anvil. Mechanical acceptors typically discourage stringing with a gravity gate that can jam. Also, mechanical acceptors become dirty in a short period of time. Rocker pivot shafts and anvils wear out. These problems require a great deal of continued maintenance. Moreover, as the mechanical acceptors wear, they become less accurate and the acceptance of slugs increases.
Some acceptors attempt to determine mass of a coin with an oscillator circuit. Mass detecting oscillators have the drawback that they tend to accept slugs and washers.
A number of electronic coin acceptors have been developed which use the principles of induction, mutual induction, inductive reactance and/or capacitive reactance to perform various tests (for example, to test for velocity and acceleration) but such method require complicated and correspondingly costly apparatus. Some also utilize rotating discs or tables to rotate magnetic fields or the coin itself as a part of the coin testing procedure, thereby tending to slow down the process. Others utilize meandering or circular coin tracks, inclined planes or ramps to perform dimensioning and other tests which also tend to slow down the testing procedure. In consequence of the jamming potential, some of these acceptors must have provision for opening of the coin track, adding to the complexity and cost.
Other coin detectors incorporate light responsive detectors serving as switches to open and close various circuit elements. Typically, the light source and sensor units are located on opposite sides of the coin track requiring a somewhat complicated mechanical configuration and add cost and difficulty in the manufacture of the units.